From: "Steven M. Schweda" <sms@antinode.info>
Subject: Fix CVE-2016-9844, buffer overflow in zipinfo
Bug-Debian: https://bugs.debian.org/847486
Bug-Ubuntu: https://launchpad.net/bugs/1643750
X-Debian-version: 6.0-21

Upstream-Status: Backport
CVE: CVE-2016-9844
Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>

--- a/zipinfo.c
+++ b/zipinfo.c
@@ -1921,7 +1921,18 @@
         ush  dnum=(ush)((G.crec.general_purpose_bit_flag>>1) & 3);
         methbuf[3] = dtype[dnum];
     } else if (methnum >= NUM_METHODS) {   /* unknown */
-        sprintf(&methbuf[1], "%03u", G.crec.compression_method);
+        /* 2016-12-05 SMS.
+         * https://launchpad.net/bugs/1643750
+         * Unexpectedly large compression methods overflow
+         * &methbuf[].  Use the old, three-digit decimal format
+         * for values which fit.  Otherwise, sacrifice the "u",
+         * and use four-digit hexadecimal.
+         */
+        if (G.crec.compression_method <= 999) {
+            sprintf( &methbuf[ 1], "%03u", G.crec.compression_method);
+        } else {
+            sprintf( &methbuf[ 0], "%04X", G.crec.compression_method);
+        }
     }
 
     for (k = 0;  k < 15;  ++k)